Analyzing sexual behavior influence on vaginal microbe colonization

Mindy Miner

The vagina for health-associated microbes is like Hawaii for Seattleites: a wonderfully enticing locale if not overrun with tourists. A healthy vagina contains predominantly Lactobacillus species; but bacterial vaginosis (BV) is associated with fewer lactobacilli and a multitude of opportunistic bacteria. Antibiotic treatment for BV leads to depletion of these opportunists, but unfortunately, like unwelcome guests, they tend to return. The reemergence of protective lactobacilli, such as hydrogen peroxide-producing L. crispatus and L. jensenii, post-antibiotic therapy may create an environment that is less hospitable for these opportunists and promotes vaginal health.

The main objective of this study was to identify a possible correlation between sexual behavior and beneficial lactobacilli colonization after BV antibiotic treatment. VIDD associate member Dr. David Fredricks, VIDD affiliate Dr. Caroline Mitchell, and collaborators from the University of Washington analyzed a cohort of 44 women in Seattle that were diagnosed and treated for BV who had reported sex with at least one woman during the prior year (a community with an especially high prevalence of BV). The authors characterized the patients’ vaginal microbiota at the time of BV diagnosis and post-treatment (approximately 4 weeks later) and concomitantly recorded sexual behavior: number of partners; oral-, digital-, toy-, and penile-vaginal sex; and use of vaginal lubricant. At time of BV diagnosis, all 44 women were colonized with L. iners, a non-hydrogen peroxide producing Lactobacillus species, and few were colonized with L. crispatus or L. jensenii. At follow-up, no sexual behaviors significantly influenced BV cure or the presence or absence of L. crispatus and L. jensenii; however L. jensenii colonization was associated with treatment success. At follow-up, only 18 women were colonized with hydrogen peroxide-producing lactobacilli: 6 with both L. crispatus and L. jensenii, and 6 each with one or the other species. In the 12 women colonized with L. crispatus, digital- and oral-vaginal sex were the only behaviors that significantly correlated with the concentration of beneficial lactobacilli; these behaviors showed an inverse association with L. crispatus levels. No behaviors were associated with quantity of L. jensenii. The authors concluded that after antibiotic therapy, colonization with protective Lactobacillus species was infrequent and associated with few sexual behaviors. The frequent failure to colonize with beneficial Lactobacillus species may facilitate the re-emergence of BV-associated bacteria after antibiotic treatment.